Technical Field
The present invention relates to a steering lock device for performing the steering lock and release thereof by the driving of a motor.
Related Art
In order to prevent the vehicle theft frequently occurring in recent years, a so-called smart entry system has been suggested which includes a transmitting means portable by a driver and capable of transmitting a vehicle-specific ID code and a receiving means capable of receiving the ID code and which enables various vehicle-operations including an engine start under the condition that the ID code received by the receiving means is a regular one. For example, in the case of a smart entry system of a motorcycle, when a driver carrying a transmitting means (electronic key) operates an access key, a receiving means on the vehicle side receives the ID code transmitted from the transmitting means and it is determined whether or not the ID code is a regular one registered in advance.
Then, when it is determined that the received ID code is the regular ID code, a power supply of a vehicle is turned on and an engine is started by pressing a start button or the like. In this way, it is possible to enable various vehicle-operations including an engine start without using a mechanical key such as an ignition key. Further, it is possible to reliably prevent the theft of a vehicle or an illegal operation for a vehicle, or the like.
By the way, in a motorcycle or the like, typically, a steering lock device is provided which performs the steering lock by rotating an ignition key inserted through a key hole in a predetermined direction and thus locking a lock bar to a steering (a rotation shaft of a handle bar, or the like). However, this steering lock device is difficult to be applied to a vehicle including a smart entry system where an operation by the ignition key as described above is not required.
Therefore, the present applicant has suggested a steering lock device as disclosed in Patent Documents 1 and 2, for example. According to this related-art steering lock device, the steering lock is performed by a manual operation to press a press button and the release of the steering lock is performed by an electric power. Therefore, a mechanical key such as an ignition key is not required at the time of performing the steering lock and release thereof, and thus, the steering lock device can be easily applied to a smart entry system.
Patent Document 1: Japanese Patent Laid-Open Publication No. 2005-075307
Patent Document 2: Japanese Patent Laid-Open Publication No. 2006-327304
However, in the related-art steering lock device, the steering lock is released in such a way that the driving force of the motor is transmitted to a cam or a latch mechanism, and thus, the lock bar is retreated from the projected state to the retracted state. Therefore, an actuation space for the cam or the latch mechanism is required, and hence, there is a problem that the whole size of the device is increased.
However, in the related-art steering lock device, it is required to press an operation button at the time of performing the steering lock, and thus, there is a problem that it is not possible to perform both the steering lock and the release thereof by an electric power. Thus, the present applicant has considered that both the steering lock and the release thereof are caused to be performed by an electric power by transmitting the driving force of the motor to the feed screw member via the gear member and causing the lock bar to advance or retreat. However, in this case, an overload occurs when the locking of the lock bar to the steering is not favorably performed at the time of causing the lock bar to advance, and thus, there is a problem that defects occur in the motor or the like.